Did you reflash for your new tire size? If you didn’t, your MPG will be off by roughly 2%.Sahara 4-door with Rubicon Take-off wheels (KO2s) On a trip to and Missouri from Texas and back I averaged 20MPG (3.6 auto) There were some hills involved especially once you pass Crowley's Ridge in Arkansas. I'm happy with the mileage, didn't buy the Jeep for MPG. I did notice that with a strong headwind it doesn't take much to keep the Jeep out of 8th gear and the mileage (instantanous) drops substantially down to 14-18MPG. A few times I had to go to manual mode to make it go back to 8th. If you are running stock sport or sahara gearing with larger tires, I can see how your mileage would suffer. all of this was at my highway avg 70-75mph and a top speed of 86 according to the Nav system.